Piercing Nut Transfer Mechanism Interference
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Solution Overview
Problem
In high-stress type piercing nut manufacturing, the transfer of nut blanks to subsequent processes is hindered due to weakened spring tension in the transfer mechanism, leading to potential roughening or cracking of the piercing punch and stoppages in long-time operations.
Innovation Solution
The use of knockout pins to push out and hold nut blanks securely between transfer mechanism fingers, eliminating interference with the piercing punch and ensuring smooth transfer to the next process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If spring-activated fingers are used to hold and transfer nut blanks, then the transfer mechanism is simple and cost-effective, but the spring tension weakens over time causing transfer failures
Solution Approach 1:
A finger-operated pusher is introduced as an intermediary component between the spring-activated fingers and the nut blank. The pusher receives activation from the fingers and transfers the pushing force to the nut blank, isolating the spring mechanism from direct contact with the workpiece. This mediator allows the spring to maintain simple tensioning without bearing the full operational stress, thereby improving reliability while preserving structural simplicity.
Solution Approach 2:
The transfer function is segmented into multiple components: the spring-activated fingers provide activation force, the finger-operated pusher provides direct contact and force transmission, and the nut blank receives the pushing force. This segmentation distributes the mechanical stress across multiple elements, preventing the spring from experiencing cumulative damage while maintaining the overall simplicity of the mechanism.
2Productivity
If the piercing punch pushes out the nut blank, then the process is integrated and efficient, but the punch tip interferes with the nut blank causing roughening or cracking
Solution Approach 1:
The function of pushing out the nut blank is extracted from the piercing punch and assigned to a dedicated finger-operated pusher. The piercing punch is relieved of this secondary function and only performs its primary piercing task, eliminating the interference between the punch tip and nut blank that causes surface defects. This separation maintains manufacturing efficiency while improving surface quality.
Solution Approach 2:
The finger-operated pusher acts as an intermediary between the forming die and the nut blank for the ejection function. Instead of the piercing punch directly contacting and pushing the nut blank (causing damage), the pusher mediates this interaction, providing a dedicated ejection mechanism that protects the nut blank surface while maintaining process integration.
3Reliability
If high spring tension is used to activate transfer fingers, then transfer reliability is maintained, but the piercing punch suffers from roughening or cracking due to counteracting stress
Solution Approach 1:
The finger-operated pusher serves as a mechanical intermediary that decouples the high spring tension from the piercing punch. The spring activates the fingers, which then activate the pusher, which finally contacts the nut blank. This multi-stage transmission allows the spring to maintain high tension for reliable activation without directly transmitting stress to the piercing punch, preserving punch integrity while ensuring transfer reliability.
Solution Approach 2:
The force transmission path is segmented into distinct stages: spring tension activates fingers, fingers activate the pusher mechanism, and the pusher applies force to the nut blank. This segmentation isolates the piercing punch from the high-stress spring activation process, allowing the spring to operate at high tension for reliability while the punch remains protected from damaging stresses.
Data Source
Figure 1
Figure 2(a)~2(d)
Figure 3
AI summary
A piercing nut manufacturing apparatus uses a nut former for forming a nut blank 11 for a high stress type piercing nut 1. The undercut screw-hole 12 is pierced and the end surface portion of pilot portion 13 radially widened, and the four diagonal corner end surfaces of nut blank 11b finished with the forming process of slanting and enlarging the peripheral side wall surface of pilot portion 13 for defining annular groove 15 are pushed out by four knockout pins 77 and then pushed in between a pair of fingers 58, 58 of a transfer mechanism located in the vicinity of end surface of a die 53.